Delayed Onset of Voice Activity Detection for Jitter Adaptation

ABSTRACT

Disclosed are various systems and methods for controlling a voice activity detector. In one example approach, a method is provided in which a voice over Internet protocol (VOIP) session is initiated in a first gateway with a second gateway. A plurality of jitter adaptation packets are transmitted from the first gateway to the second gateway. Also, the voice activity detector is disabled in the first gateway during the transmission of the jitter adaptation packets. The voice activity detector is enabled in the first gateway after the transmission of the jitter adaptation packets.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to,co-pending U.S. patent application entitled “Delayed Onset VoiceActivity Detect for Jitter Adaptation” filed on Jul. 22, 2005, andassigned application Ser. No. 11/187,752, which is incorporated hereinby reference in its entirety.

BACKGROUND

When a Voice-Over-Internet-Protocol (VOIP) begins, a receiving endpointmust adapt itself to the jitter behavior of the packet switched network.Unfortunately, the number of packets available for jitter adaptation bya given receiving endpoint may not be enough for proper jitteradaptation until individuals or devices transmit sound in the form ofvoice communication or data communication. This results in degradationof the valuable voice/data signal received at the receiving endpoint.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention can be understood with reference to the followingdrawings. The components in the drawings are not necessarily to scale.Also, in the drawings, like reference numerals designate correspondingparts throughout the several views.

FIG. 1 is a block diagram of the devices and networks involved in a VOIPsession according to an embodiment of the present invention;

FIG. 2 is a block diagram of a gateway employed as one of the devicesconducting the VOIP session of FIG. 1 according to an embodiment of thepresent invention;

FIG. 3 is a flow chart that illustrates one example of a voice activitydetector (VAD) control employed in the gateway of FIG. 2 according to anembodiment of the present invention; and

FIG. 4 is a flow chart that illustrates one example of a voice activitydetector (VAD) control employed in the gateway of FIG. 2 according to anembodiment of the present invention.

DETAILED DESCRIPTION

Referring to FIG. 1, shown is a Voice-over-Internet Protocol (VOIP)network 100 that includes a calling device 103 and a called device 106.The calling device 103 and the called device 106 may each comprise, forexample, a telephone, a facsimile machine, a data terminal device (DTE)or other device. The calling device 103 is in data communication withthe called device 106 through a first gateway 109, a data communicationsnetwork 113, and a second gateway 116. The data communications network113 may comprise, for example, the Internet, a wide area network, orother network.

The calling telephone 103 and the called telephone 106 may establishcommunication 119 with the first gateway 109 and the second gateway,respectively, by a direct link such as, for example, through a wire orvia a wireless connection, or through a telecommunications network, etc.

A user may manipulate the calling device 103 to initiate a VOIP sessionwith the called device 106. In this respect, the user manipulates thecalling device 103 to establish the session by, for example, dialing atelephone number on the calling device 103 that identifies the calleddevice 106 in the case that the calling and called devices 103 and 106are telephones or facsimile machines. The calling device 103communicates with the first gateway 109 that, in turn, initiates theVOIP session with the second gateway 116 over the data communicationsnetwork 113. The second gateway 116 establishes communication with thecalled device 106, thereby establishing the VOIP session between thecalling and called devices 103 and 106.

During the course of the VOIP session between the calling and calleddevices 103 and 106, both the first and second gateways 109 and 116temporarily store a plurality of packets in a “jitter” buffer. Thejitter buffer allows the first and second gateways 109 and 116 tocompensate for the latency of the data communications network 113. Thelatency of the data communications network 113 may vary over time. Inthis respect, the term “jitter” refers to the distortion of thetransmission of a signal during a VOIP session due to the varyinglatency of the data communications network 113. In order to reduce theeffects of jitter, both the first and second gateways 109 and 116include a jitter adapter that determines a desirable number of packetsthat are stored in a jitter buffer in an attempt to make sure that thegateway 109 or 116 has a desirable number of data packets on hand fromwhich the respective voice or data signal may be reproduced and passedon to the calling or called devices 103 or 106 The desirable number ofdata packets is specified so as not to create too much delay that mightotherwise degrade the communications performed during the VOIP session.

In order to perform jitter adaptation, the jitter adapter in the firstand second gateways 109 and 116 may add periods of silence into the datastream, or may discard packets as is deemed necessary to provide optimumperformance. At or near the startup of the VOIP session, the jitteradaptation that is performed is somewhat aggressive, where a defaultnumber of packets are stored in the jitter buffer of the respectivegateway 109 and 116. From there, the respective jitter adapter acts todetermine the optimum number of packets that are to be stored in thejitter buffer during the VOIP session based upon the latency of the datacommunications network 113 experienced during the VOIP session.

Each of the gateways 109 and 116 also include a voice activity detector(VAD) that is employed to detect when voice or other communicationactivity occurs that is to be transmitted to the other gateway 109 or116. In this respect, the transmission of a signal by either gateway 109or 116 to the other one of the gateways 109 or 116 occurs only whenthere is voice or other communication activity to transmit. This reducesthe amount of data communication that is sent over the datacommunications network 113, thereby preventing the transmission of datathat unnecessarily uses up network bandwidth.

According to various embodiments of the present invention, when the VOIPsession is first established between the first and second gateways 109and 116, the first gateway 109 transmits a plurality of jitteradaptation packets to the second gateway 116. The jitter adaptationpackets transmitted from the first gateway 109 to the second gateway 116allow the second gateway 116 to adapt its jitter buffer as can beappreciated. Similarly, the second gateway 116 transmits jitteradaptation packets to the first gateway 109 as soon as the secondgateway 116 is able so that the first gateway 109 may perform jitteradaptation. In this respect, the second gateway 116 transmits the jitteradaptation packets as soon as it has received the information from thefirst gateway 109 indicating, among other parameters, the IP address ofthe first gateway 109, etc., thereby providing the information thatallows the jitter adaptation packets to be sent to the first gateway109.

According to various embodiments of the present invention, during thetransmission of the jitter adaptation packets by either the first orsecond gateway 109 or 116 to the other one of the gateways 109 or 116,the voice activity detector in the respective first or second gateway109 or 116 is disabled. As contemplated herein, the voice activitydetector may be disabled by either ignoring its output, disabling itsoperation outright, or performing some other operation so that, ineffect, the voice activity detector is no longer able to exert controlover whether packets are transmitted to the network 113 by therespective gateway 109 or 116. It follows then, that the voice activitydetector may be enabled by performing an action that is opposite of thatperformed to disable the voice activity detector as described above. Inthis respect, the voice activity detector controls the “DiscontinuousTransmission” (DTX) of the respective gateway 109/116. DiscontinuousTransmission refers to the fact that when the voice activity detector isenabled, the transmission is not continuous, but occurs when voice orother activity is detected. By disabling the voice activity detector asdescribed above, discontinuous transmission is correspondingly disabled.When discontinuous transmission is disabled, a continuous stream ofpackets is transmitted.

Once a desired number of jitter adaptation packets have been transmittedby the respective gateway 109 or 116, then the voice activity detectorof the respective gateway 109 or 116 is enabled to limit thetransmission to actual voice or other communication. By disabling thevoice activity detector in this manner, in a typical situation aplurality of packets of “silence” are inevitably transmitted at thebeginning of the VOIP session that do not include voice or othercommunication. These packets are the jitter adaptation packets. In thisrespect, jitter adaptation packets are defined herein as packetstransmitted by a first one of the gateways 109 or 116 to a second one ofthe gateways 109 or 116 to facilitate jitter adaptation in the secondone of the gateways 109 or 116. While it is typical that silence istransmitted with such packets, it is possible that some sound may betransmitted in the jitter adaptation packets as well.

In this respect, the jitter adaptation packets may comprise the initialor first number of the packets transmitted, for example, by the firstgateway 109 to the second gateway 116. Alternatively, the jitteradaptation packets may be transmitted, for example, by the first gateway109 to the second gateway 116 after the first gateway 109 has received afirst packet from the second gateway 116 during the course of the setupof the VOIP session. The latter approach assumes, for example, that thefirst gateway 109 initiated the call. In this respect, the first gateway109 determines whether a packet has been received from the secondgateway 116 before transmitting the jitter adaptation packets to thesecond gateway 116. This may be advantageous as, upon receiving a firstpacket from the second gateway 116, the first gateway 109 knows that thesecond gateway 116 is ready to receive packets. This ensures that thesecond gateway 116 will receive most, if not all, of the jitteradaptation packets transmitted by the first gateway 109 barring anylosses that may normally occur on the network 113.

In one embodiment, a minimum required number of the jitter adaptationpackets are transmitted from the first gateway 109 to the second gateway116. This minimum required number of the jitter adaptation packets is atleast as great as the number of jitter adaptation packets needed toallow a jitter adapter to substantially adapt the number of packets heldin a jitter buffer associated with the jitter adapter. In order toensure that the minimum required number of jitter adaptation packets aretransmitted, the first gateway 109 may employ one of a number ofapproaches described below in order to track the approximate totalnumber of jitter adaptation packets that have been transmitted to thesecond gateway 116. In each of these approaches, it is assumed, forexample, that the first gateway 109 is associated with the callingdevice 109 and initiates the VOIP session with the second gateway 116.

In one embodiment, the first gateway 109 counts the jitter adaptationpackets transmitted to the second gateway 116 to ensure that the secondgateway 116 receives a predefined quantity of jitter adaptation packets.The predefined quantity of jitter adaptation packets is specified so asto ensure, to the extent possible, that the minimum required number ofjitter adaptation packets have been transmitted. Likewise, the secondgateway 116 may be configured to count the number of jitter adaptationpackets transmitted to the first gateway 109 to ensure, to the extentpossible, that the predefined quantity of jitter adaptation packets havebeen transmitted.

In one implementation, the counting of the jitter adaptation packets inthe first gateway 109 may begin upon transmission of the very firstpacket by the first gateway 109 to the second gateway 116. In thisimplementation, given that the first gateway 109 does not initially knowwhether the second gateway 116 is receiving the jitter adaptationpackets as the first gateway 109 has yet to receive any packets from thesecond gateway 116 before the first gateway 109 transmits jitteradaptation packets, it may be the case that the second gateway 116 doesnot actually receive the first several jitter adaptation packets fromthe first gateway 109. As such, in one example implementation, thepredefined quantity of jitter adaptation packets transmitted by thefirst gateway 109 may include an estimated number of jitter adaptationpackets that may be potentially discarded in addition to the minimumrequired number of adaptation packets to ensure that the second gateway116 receives the minimum required number of jitter adaptation packetsfor proper jitter adaptation, where it is contemplated that at least afew of the jitter adaptation packets may be lost.

In a second implementation, the counting of the jitter adaptationpackets may begin after a first packet has been received by the firstgateway 109 from the second gateway 116 during the setup of the VOIPsession. Given that the first gateway 109 has initiated the VOIPsession, the fact that a packet has been received by the first gateway109 from the second gateway 116 indicates that the second gateway 116 isreceiving packets from the first gateway 109. The predefined quantity ofjitter adaptation packets transmitted by the first gateway 109 may bespecified, for example, as the minimum required number of jitteradaptation packets needed or other number. The predefined quantity ofjitter adaptation packets may be the minimum required number of jitteradaptation packets since the first gateway 109 knows that the secondgateway 116 is receiving most, if not all of the packets at such time.

The second gateway 116 may also count the number of jitter adaptationpackets it sends to the first gateway 109. The predefined quantity ofjitter adaptation packets specified for transmission may be the minimumrequired number of jitter adaptation packets since the second gateway116 knows that the first gateway 109 is receiving packets as the VOIPsession was initiated by the first gateway 109. Thus, the second gateway116 can assume that most if not all of the jitter adaptation packetshave been received by the first gateway 109.

In another approach, the determination as to whether the predefinedquantity of jitter packets has been transmitted from the first gateway109 to the second gateway 116 is made by tracking a time period in thefirst gateway 109 within which the jitter adaptation packets aretransmitted. This assumes, for example, that the jitter adaptationpackets are transmitted at a given rate. The time period may begin, forexample, at the initial startup of the VOIP session such as, forexample, before the transmission of jitter adaptation packets begins. Insuch case, a timer may be initiated in the first gateway before thetransmission of the jitter adaptation packets to the second gateway totrack the passing of the time period.

The time period may be specified so as to ensure to the extent possiblethat the predefined quantity of packets transmitted includes the minimumrequired number of jitter adaptation packets needed to substantiallyadapt the second gateway 116, assuming the packets are transmitted at aknown rate. In this respect, the predefined quantity of jitteradaptation packets includes an estimated number of potentially discardedjitter adaptation packets due to the fact that the second gateway 116may not be initially ready to receive some of the jitter adaptationpackets transmitted as was discussed above.

Alternatively, the time period tracked by the first gateway 109 maybegin, for example, after a first packet has been received from thesecond gateway 116. By virtue of the fact that a first packet has beenreceived from the second gateway 116, then the first gateway 109 knowsthat the second gateway 116 is ready to receive the jitter adaptationpackets. In such case the time period may be specified so as to ensureto the extent possible that the minimum number of jitter adaptationpackets needed for jitter adaptation are transmitted.

Turning to FIG. 2, shown is a block diagram that provides one example ofa gateway 109/116, according to an embodiment of the present invention.The gateway 109/116 includes a jitter buffer 123 into which data fromthe data communications network 113 is placed. The jitter buffer 123 isadapted by the jitter adapter 126 that determines the number of datapackets stored in the jitter buffer 123 during communications with thetransmitting gateway 109/113 based upon the jitter behavior of thenetwork 113. The gateway 109/116 includes a decoder 129 that decodes thedata packets received and generates the corresponding analog voice ordata signal that is applied to the respective device 103/106 (FIG. 1)such as a telephone or facsimile machine. The gateway 109/116 alsoincludes an encoder 133 that adapts an analog voice signal or datasignal from the calling or called device 103/106 and converts the signalto digital data that is packaged into packets that are then transmittedto the receiving gateway 109/116 via the data communications network113.

The gateway 109/116 also includes a voice activity detector (VAD) 136that determines whether the encoder 133 is to generate packetsrepresentative of the signal received from the respective device103/106. In this respect, the VAD 136 receives the signal from thecalling or called device 103/106 and detects whether a signal is beinggenerated that is to be transmitted across the communications network113 that is of value as opposed to signals of little or no value such assilence. A signal that is of value may be, for example, a voice signalor data signal. In the case that the signal is silence, it may be thatstatic is transmitted or background noise generated by the calling orcalled device 103/106. The VAD 136 enables the encoder 133 to generateand transmit packets to the data communications network 113 based uponthe signal received from the calling or called device 103/106accordingly. Thus, if there is no voice activity, for example, then theVAD 136 prevents the encoder 133 from sending a signal to the datacommunications network 113.

The gateway 109/116 also includes a VAD control 139. The VAD control 139determines whether the operation of the voice activity detector 136 isenabled. When the voice activity detector 136 is disabled, the encoder133 continuously generates packets associated with the signal receivedfrom the calling and called devices 103/106. In this respect, theencoder 133 transmits data packets 113 without regard as to the natureof the signal received from a calling or called device 103/106. When theVAD 136 is enabled, then it controls when the encoder 133 generatespackets based upon the nature of the signal received from the calling orcalled devices 103/106 as described above.

The VAD control 139 determines when the VAD 136 is to be enabled.According to the various embodiments of the present invention, the VADcontrol 139 disables the VAD 136 when the jitter adaptation packets arebeing transmitted by the gateway 109/116. In this respect, the VADcontrol 139 may disable the VAD 136 during the specified time periods asdescribed above, or the VAD control 139 may track the number of packetstransmitted from the encoder 133 to the data communications network 113in order to ensure that the appropriate number of jitter adaptationpackets have been transmitted as was described above.

Referring next to FIG. 3, shown is a flow chart that provides oneexample of the operation of the VAD control 139, denoted herein as VADcontrol 139 a, according to an embodiment of the present invention.Alternatively, the flow chart of FIG. 3 may be viewed as depicting stepsof an example of a method implemented in the computer system 100 tocontrol enabling and disabling of the VAD 136 (FIG. 2) as describedherein. The functionality of the VAD control 139 a as depicted by theexample flow chart of FIG. 3 may be implemented, for example, in anobject oriented design or in some other programming architecture.Assuming the functionality is implemented in an object oriented design,then each block represents functionality that may be implemented in oneor more methods that are encapsulated in one or more objects. The VADcontrol 139 a may be implemented using any one of a number ofprogramming languages such as, for example, C, C++, Assembly, or otherappropriate programming languages.

The VAD control 139 a is executed, for example, in the first gateway 109in which jitter adaptation packets are transmitted after a first packethas been received from the second gateway 116 as described above. Inthis scenario, the first gateway 109 is associated with the callingdevice 103 and initiates the VOIP session as shown in FIG. 1.Alternatively, the VAD control 139 may be executed in the second gateway116 as described below.

The VAD control 139 a is executed upon the initiation of a VOIP sessionbetween, for example, the first gateway 109 and the second gateway 116(FIG. 1). To begin, in box 143 the VAD control 139 a disables the voiceactivity detector 136. Thereafter, in box 146, assuming the VAD control139 a is executed in the first gateway 109, the VAD control 139 adetermines whether a first packet has been received from the secondgateway 116. Alternatively, if the VAD control 139 a is executed in thesecond gateway 116, then box 146 may be skipped as it is assumed thatthe first gateway 103 is receiving packets as it initiated the VOIPsession.

Next, in box 149, the VAD control 139 a commences counting transmittedpackets if such an approach is employed to track whether the minimumrequired number of jitter adaptation packets is transmitted to the peergateway 109/116. Alternatively, the VAD control 139 a may initiate theoperation of a timer with which to track a time period during whichjitter adaptation packets are transmitted to the peer gateway 109/116.Then, in box 153, the VAD control 139 a determines whether the packetcount has reached a predefined value indicating that at least theminimum required number of jitter adaptation packets has beentransmitted to the opposing gateway 109/116. Alternatively, in box 153,the VAD control 139 a may determine whether the time period tracked bythe timer initiated in box 149 has elapsed. Assuming that the packetcount has reached the predefined value or the time period tracked by thetimer initiated in box 149 has elapsed, then the VAD control 139 aproceeds to box 156 in which the voice activity detector 136 is enabledfor future operation during the VOIP session.

Referring next to FIG. 4, shown is a flow chart that provides anotherexample of the operation of the VAD control 139, denoted herein as VADcontrol 139 b, according to an embodiment of the present invention.Alternatively, the flow chart of FIG. 4 may be viewed as depicting stepsof an example of a method implemented in the computer system 100 tocontrol enabling and disabling of the VAD 136 (FIG. 2) as describedherein. The functionality of the VAD control 139 b as depicted by theexample flow chart of FIG. 4 may be implemented, for example, in anobject oriented design or in some other programming architecture.Assuming the functionality is implemented in an object oriented design,then each block represents functionality that may be implemented in oneor more methods that are encapsulated in one or more objects. The VADcontrol 139 b may be implemented using any one of a number ofprogramming languages such as, for example, C, C++, Assembly, or otherappropriate programming languages

The VAD control 139 b is implemented in approaches where the packetcount or timer is initiated in the first gateway 109 at the beginning ofthe VOIP session as opposed to when a first packet has been received bythe first gateway 109 from the second gateway 116 as described above. Inthis respect, the packet count or timer operation is potentiallyinitiated before it is absolutely known that the opposing gateway109/116 has commenced receiving packets as was described above.

Beginning with box 163, the VAD control 139 b commences counting jitteradaptation packets transmitted to the second gateway 116, or, a timer isinitiated to track a time period within which the jitter adaptationpackets are transmitted to the second gateway 116. Thereafter, in box166, the VAD control 139 b disables the voice activity detector 136(FIG. 2). Next, in box 169, the VAD control 139 b determines whether thepredefined value has been reached for the packet count, or whether therespective time period tracked by the timer has elapsed. If so, then inbox 173, the VAD control 139 b enables the voice activity detector 136.Thereafter, the VAD control 139 b ends as shown.

Although the VAD control 139 may be embodied in software or codeexecuted by general purpose hardware, or embodied in dedicated hardwareor a combination of software/general purpose hardware and dedicatedhardware. If embodied in dedicated hardware, the VAD control 139 can beimplemented as a circuit or state machine that employs any one of or acombination of a number of technologies. These technologies may include,but are not limited to, discrete logic circuits having logic gates forimplementing various logic functions upon an application of one or moredata signals, application specific integrated circuits havingappropriate logic gates, programmable gate arrays (PGA), fieldprogrammable gate arrays (FPGA), or other components, etc. Suchtechnologies are generally well known by those skilled in the art and,consequently, are not described in detail herein.

The flow charts of FIGS. 3 and 4 show the architecture, functionality,and operation of an implementation of the VAD control 139. If embodiedin software, each block may represent a module, segment, or portion ofcode that comprises program instructions to implement the specifiedlogical function(s). The program instructions may be embodied in theform of source code that comprises human-readable statements written ina programming language or machine code that comprises numericalinstructions recognizable by a suitable execution system such as aprocessor in a computer system or other system. The machine code may beconverted from the source code, etc. If embodied in hardware, each blockmay represent a circuit or a number of interconnected circuits toimplement the specified logical function(s).

Although the flow charts of FIGS. 3 and 4 show a specific order ofexecution, it is understood that the order of execution may differ fromthat which is depicted. For example, the order of execution of two ormore blocks may be scrambled relative to the order shown. Also, two ormore blocks shown in succession in FIGS. 3 and 4 may be executedconcurrently or with partial concurrence. In addition, any number ofcounters, state variables, warning semaphores, or messages might beadded to the logical flow described herein, for purposes of enhancedutility, accounting, performance measurement, or providingtroubleshooting aids, etc. It is understood that all such variations arewithin the scope of the present invention.

Also, where the VAD control 139 comprises software or code, it can beembodied in any computer-readable medium for use by or in connectionwith an instruction execution system such as, for example, a processorin a computer system or other system. In this sense, the logic maycomprise, for example, statements including instructions anddeclarations that can be fetched from the computer-readable medium andexecuted by the instruction execution system. In the context of thepresent invention, a “computer-readable medium” can be any medium thatcan contain, store, or maintain the VAD control 139 for use by or inconnection with the instruction execution system. The computer readablemedium can comprise any one of many physical media such as, for example,electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor media. More specific examples of a suitablecomputer-readable medium would include, but are not limited to, magnetictapes, magnetic floppy diskettes, magnetic hard drives, or compactdiscs. Also, the computer-readable medium may be a random access memory(RAM) including, for example, static random access memory (SRAM) anddynamic random access memory (DRAM), or magnetic random access memory(MRAM). In addition, the computer-readable medium may be a read-onlymemory (ROM), a programmable read-only memory (PROM), an erasableprogrammable read-only memory (EPROM), an electrically erasableprogrammable read-only memory (EEPROM), or other type of memory device.

Although the invention is shown and described with respect to certainembodiments, it is obvious that equivalents and modifications will occurto others skilled in the art upon the reading and understanding of thespecification. The present invention includes all such equivalents andmodifications, and is limited only by the scope of the claims.

1. A method for controlling a voice activity detector, comprising thesteps of: initiating in a first gateway a voice over internet protocol(VOIP) session with a second gateway; transmitting a plurality of jitteradaptation packets from the first gateway to the second gateway;disabling the voice activity detector in the first gateway during thetransmission of the jitter adaptation packets; and enabling the voiceactivity detector in the first gateway after the transmission of thejitter adaptation packets; wherein the jitter adaptation packetstransmitted from the first gateway to the second gateway comprise aninitial number of packets transmitted by the first gateway to the secondgateway.
 2. (canceled)
 3. The method of claim 1, further comprising thestep of determining whether a packet has been received in the firstgateway from the second gateway, wherein the jitter adaptation packetsare transmitted after the packet has been received in the first gateway.4. The method of claim 3, further comprising the step of counting thejitter adaptation packets transmitted to the second gateway after thepacket has been received in the first gateway, wherein the voiceactivity detector is enabled after a predefined quantity of the jitteradaptation packets is transmitted from the first gateway to the secondgateway.
 5. The method of claim 3, further comprising the step oftransmitting the jitter adaptation packets to the second gateway for apredefined period of time after the packet has been received in thefirst gateway, wherein the voice activity detector is enabled after thepredefined period of time has elapsed.
 6. The method of claim 1, furthercomprising the step of initiating a timer in the first gateway before atransmission of the jitter adaptation packets from the first gateway tothe second gateway, wherein the voice activity detector is enabled whenthe timer indicates that a predefined period of time has elapsed.
 7. Themethod of claim 1, wherein a minimum required number of the jitteradaptation packets is transmitted from the first gateway to the secondgateway, wherein the minimum required number of the jitter adaptationpackets is at least as great as an amount of jitter adaptation packetsfor a jitter adaptor to substantially adapt the number of packets heldin a jitter buffer associated with the jitter adaptor.
 8. A system in afirst gateway for controlling a voice activity detector (VAD),comprising: a VAD controller configured to disable the VAD in the firstgateway during a transmission of a plurality of jitter adaptationpackets to a second gateway; and the VAD controller being furtherconfigured to enable the VAD in the first gateway after the transmissionof the jitter adaptation packets; wherein the jitter adaptation packetsfurther comprise an initial number of packets transmitted by the firstgateway to the second gateway.
 9. (canceled)
 10. The system of claim 8,wherein the VAD controller is further configured to determine whether apacket has been received in the first gateway from the second gateway,wherein the jitter adaptation packets are transmitted after the packethas been received in the first gateway.
 11. The system of claim 10,wherein the VAD controller is further configured to count the jitteradaptation packets transmitted to the second gateway after the packethas been received in the first gateway, and to enable the voice activitydetector after a predefined quantity of the jitter adaptation packetsare transmitted from the first gateway to the second gateway.
 12. Thesystem of claim 10, wherein the VAD controller tracks a passing of apredefined period of time after the packet has been received in thefirst gateway, wherein the jitter adaptation packets are transmitted tothe second gateway during the predefined period of time and the VADcontroller is configured to enable the VAD after the predefined periodtime has elapsed.
 13. The system of claim 8, wherein the VAD controlleris further configured to track a predefined period of time with a timerin the first gateway, the predefined period of time beginning before atransmission of the jitter adaptation packets from the first gateway tothe second gateway, the jitter adaptation packets being transmittedduring the predefined period of time, wherein the VAD controller isconfigured to enable the VAD after the predefined period of time haselapsed.
 14. The system of claim 8, wherein a minimum required number ofthe jitter adaptation packets is transmitted from the first gateway tothe second gateway, wherein the minimum required number of the jitteradaptation packets is at least as great as an amount of jitteradaptation packets for a jitter adaptor to substantially adapt thenumber of packets held in a jitter buffer associated with the jitteradaptor.
 15. A system in a first gateway for controlling a voiceactivity detector (VAD), comprising: means for disabling the VAD in thefirst gateway during a transmission of a plurality of jitter adaptationpackets to a second gateway; and means for enabling the VAD in the firstgateway after the transmission of the jitter adaptation packets; whereinthe jitter adaptation packets further comprise an initial number ofpackets transmitted by the first gateway to the second gateway. 16.(canceled)
 17. The system of claim 15, further comprising means fordetermining whether a packet has been received in the first gateway fromthe second gateway, wherein the jitter adaptation packets aretransmitted after the packet has been received in the first gateway. 18.The system of claim 17, further comprising: means for counting thejitter adaptation packets transmitted to the second gateway after thepacket has been received in the first gateway; and means for enablingthe voice activity detector after a predefined quantity of the jitteradaptation packets are transmitted from the first gateway to the secondgateway.
 19. The system of claim 17, further comprising means fortracking a passing of a predefined period of time after the packet hasbeen received in the first gateway, wherein the jitter adaptationpackets are transmitted to the second gateway during the predefinedperiod of time and the VAD controller is configured to enable the VADafter the predefined period of time has elapsed.
 20. The system of claim15, further comprising: means for tracking a predefined period of timewith a timer in the first gateway, the predefined period of timebeginning before a transmission of the jitter adaptation packets fromthe first gateway to the second gateway, the jitter adaptation packetsbeing transmitted during the predefined period of time; and wherein themeans for enabling the VAD in the first gateway after the transmissionof the jitter adaptation packets further comprises means for enablingthe VAD after the predefined period of time has elapsed.